It's raining=It's rainy吗?Why?

It's raining=It's rainy吗?Why? It's rainy =it is raining It's raining now.和It's rainy now哪个对?rainy和raining不是通用吗? It's raining为什么不用rainy 为什么用raining 而It's cold又用cold? it's raining or it's rainy or it's rain 哪个对? It's was（raining/rainy) yesterday.用什么?为什么? it's ____ today.(rain ) 填 rainy,还是raining 天气用法It's raining!为什么不是rainy?为什么不是It's clouding 而是 cloudy 请问It's rainy. 与It's raining.的区别是? It's raining now.和It's rainy now哪个对 It’s rainy it s rainy today.